1. Field of the Invention
This invention relates to an apparatus for the production of corrugated cardboard having a cover-lining on at least one side.
2. Description of the Prior Art
Apparatus for the production of a corrugated cardboard having a cover lining on at least one side, with an upper grooved roll, a lower grooved roll which has outwardly open annular grooves in distribution over its length to which a suction source is connected by means of nozzles held by carriers, of which nozzles two in each case, lying opposite to one another, are arranged fitting into an annular groove in the region of the paper web entry and exit on the lower grooved roll.
Such an apparatus for the production of a corrugated cardboard having a cover-lining on at least one side is known from U.S. Pat. No. 2,068,155. In this case the lower grooved roll is provided with outwardly open annular grooves arranged side-by-side. Into each annular groove there extend two mutually opposite straight nozzles which possess a rectangular cross-section. These straight nozzles are connected by way of shut-off cocks to the pipes carrying the nozzles in rows, which in turn are connected to an air suction source. It is here disadvantageous that the width of the annular grooves is large in comparison with the annular groove depth, so that the shaping of the corrugated web is impaired. Moreover these nozzle rows are not also used to promote the approach of the web to be corrugated to the lower grooved roll and its departure therefrom.
The invention is based upon the problem of improving this known apparatus in that the shaping of the web to be corrugated is improved, the adaptation of the apparatus to different web widths is simplified, stoppages of the nozzles and of the annular grooves are avoided and the suction effect is made adaptable to the working speed of the apparatus.